Just a heads up that there is not good documentation for implementing reCAPTCHA for web-to-lead. We ran into a permission error that even Salesforce support was not able to solve for us. However we evantually found in the success community someone posted the solution. I will detail here to to help others avoid this issue.
In order to create a web-to-lead form with reCAPTCHA, you have to add a "reCAPTCHA API Key Pair". When you sign up with reCAPTCHA you are given this key pair, but now you have to add it to Salesforce so you can select it with the lookup on the web-to-lead creation page. To do this you click the magnifying glass to the right of the "reCAPTCHA API Key Pair" lookup. This will take you to a lookup search page which will likely have no results. However you can click the "New" button.
When you click the "New" button, if you have an org that pre-existed Spring 2017, you will get an insufficient privileges error, unless you go to Setup/Customize/User Interface, and then click the "Show Quick Create" setting. You would never know that you need this permission to implement reCAPTCHA on a web-to-lead, but you do.
Now you are set to use reCAPTCHA! Happy spam blocking.
@Nonprofit Hub @Nonprofit Success Pack @Salesforce.org System Administrators
Thanks @Gorav Seth. I took away the Quick Create now that I have the added the key! Rule number 1 in Salesforce =Never Argue with @Steve Molis
